Search Results

Search found 916 results on 37 pages for 'stdio'.

Page 20/37 | < Previous Page | 16 17 18 19 20 21 22 23 24 25 26 27  | Next Page >

  • Segmentation fault

    - by darkie15
    #include<stdio.h> #include<zlib.h> #include<unistd.h> #include<string.h> int main(int argc, char *argv[]) { char *path=NULL; size_t size; int index ; printf("\nArgument count is = %d", argc); printf ("\nThe 0th argument to the file is %s", argv[0]); path = getcwd(path, size); printf("\nThe current working directory is = %s", path); if (argc <= 1) { printf("\nUsage: ./output filename1 filename2 ..."); } else if (argc > 1) { for (index = 1; index <= argc;index++) { printf("\n File name entered is = %s", argv[index]); strcat(path,argv[index]); printf("\n The complete path of the file name is = %s", path); } } return 0; } In the above code, here is the output that I get while running the code: $ ./output test.txt Argument count is = 2 The 0th argument to the file is ./output The current working directory is = /home/welcomeuser File name entered is = test.txt The complete path of the file name is = /home/welcomeusertest.txt Segmentation fault (core dumped) Can anyone please me understand why I am getting a core dumped error? Regards, darkie

    Read the article

  • function pointers callbacks C

    - by robUK
    Hello, I have started to review callbacks. I found this link: http://stackoverflow.com/questions/142789/what-is-a-callback-in-c-and-how-are-they-implemented which has a good example of callback which is very similar to what we use at work. However, I have tried to get it to work, but I have many errors. #include <stdio.h> /* Is the actual function pointer? */ typedef void (*event_cb_t)(const struct event *evt, void *user_data); struct event_cb { event_cb_t cb; void *data; }; int event_cb_register(event_ct_t cb, void *user_data); static void my_event_cb(const struct event *evt, void *data) { /* do some stuff */ } int main(void) { event_cb_register(my_event_cb, &my_custom_data); struct event_cb *callback; callback->cb(event, callback->data); return 0; } I know that callback use function pointers to store an address of a function. But there is a few things that I find I don't understand. That is what is meet by "registering the callback" and "event dispatcher"? Many thanks for any advice,

    Read the article

  • Incompatible types when assigning to type 'struct compartido'

    - by user1660559
    I have one problem with this code. I should create one structure and share it across 5 new process created from the father: #include <stdio.h> #include <stdlib.h> #include <sys/wait.h> #include <unistd.h> #include <sys/types.h> #include <sys/ipc.h> #include <sys/shm.h> #include <sys/sem.h> #include <time.h> struct compartido { int pid1, pid2, pid3, pid4, pid5; int propietario; int contador; int pidpadre; }; struct compartido var; int main(int argc, char *argv[]) { key_t llave1,llavesem; int idmem,idsem; llave1=ftok("/tmp",'a'); idmem=shmget(llave1,sizeof(int),IPC_CREAT|0600); if (idmem==-1) { perror ("shmget"); return 1; } var=shmat(idmem,0,0); /*This line is giving the error*/ /*rest of the code*/ } The exact error is giving is: error: incompatible types when assigning to type 'struct compartido' from type 'void *' I need to put this structure in the shared variable to be able to see and modify all those data from the 6 process (5 children and the father). What I'm doing bad? Thanks in advance and best regards,

    Read the article

  • Can someone explain me this code ?

    - by VaioIsBorn
    #include <stdio.h> #include <unistd.h> #include <string.h> int good(int addr) { printf("Address of hmm: %p\n", addr); } int hmm() { printf("Win.\n"); execl("/bin/sh", "sh", NULL); } extern char **environ; int main(int argc, char **argv) { int i, limit; for(i = 0; environ[i] != NULL; i++) memset(environ[i], 0x00, strlen(environ[i])); int (*fptr)(int) = good; char buf[32]; if(strlen(argv[1]) <= 40) limit = strlen(argv[1]); for(i = 0; i <= limit; i++) { buf[i] = argv[1][i]; if(i < 36) buf[i] = 0x41; } int (*hmmptr)(int) = hmm; (*fptr)((int)hmmptr); return 0; } I don't really understand the code above, i have it from an online game - i should supply something in the arguments so it would give me shell, but i don't get it how it works so i don't know what to do. So i need someone that would explain it what it does, how it's working and the stuff. Thanks.

    Read the article

  • c++ Mixing printf with wprintf (or cout with wcout)

    - by Bo Jensen
    I know you should not mix printing with printf,cout and wprintf,wcout, but have a hard time finding a good answer why and if it is possible to get round it. The problem is I use a external library that prints with printf and my own uses wcout. If I do a simple example it works fine, but from my full application it simply does not print the printf statements. If this is really a limitation, then there would be many libraries out there which can not work together with wide printing applications. Any insight on this is more than welcome. Update : I boiled it down to : #include <stdio.h> #include <stdlib.h> #include <iostream> #include <readline/readline.h> #include <readline/history.h> int main() { char *buf; std::wcout << std::endl; /* ADDING THIS LINE MAKES PRINTF VANISH!!! */ rl_bind_key('\t',rl_abort);//disable auto-complete while((buf = readline("my-command : "))!=NULL) { if (strcmp(buf,"quit")==0) break; std::wcout<<buf<< std::endl; if (buf[0]!=0) add_history(buf); } free(buf); return 0; } So I guess it might be a flushing problem, but it still looks strange to me, I have to check up on it.

    Read the article

  • Consulting a Prolog Source Code from within a VS2008 Solution File

    - by Joshua Green
    I have a Prolog file (Hanoi.pl) containing the code for solving the Hanoi Towers puzzle: hanoi( N ):- move( N, left, middle, right ). move( 0, _, _, _ ):- !. move( N, A, B, C ):- M is N-1, move( M, A, C, B ), inform( A, B ), move( M, C, B, A ). inform( X, Y ):- write( 'move a disk from ' ), write( X ), write( ' to ' ), writeln( Y ). I also have a C++ file written in VS2008 IDE: #include <iostream> #include <string> #include <stdio.h> #include <stdlib.h> using namespace std; #include "SWI-cpp.h" #include "SWI-Prolog.h" predicate_t phanoi; term_t t0; int main(int argc, char** argv) { long n = 5; int rval; if ( !PL_initialise(1, argv) ) PL_halt(1); PL_put_integer( t0, n ); phanoi = PL_predicate( "hanoi", 1, NULL ); rval = PL_call_predicate( NULL, PL_Q_NORMAL, phanoi, t0 ); system( "PAUSE" ); } How can I consult my Prolog source code (Hanoi.pl) from within my C++ code? Not from the Command Prompt - from the code, something like include or consult or compile? It is located in the same folder as my cpp file. Thanks,

    Read the article

  • How to avoid using the plld.exe utility in VS2008 (for linking C++ and Prolog codes)

    - by Joshua Green
    Here is my code in its entirety: Trying "listing." at the Prolog prompt that pops up when I run the program confirms that my Prolog source code has been loaded (consulted). #include <iostream> #include <fstream> #include <string> #include <math.h> #include <stdio.h> #include <stdlib.h> #include <stdafx.h> using namespace std; #include "Windows.h" #include "ctype.h" #include "SWI-cpp.h" #include "SWI-Prolog.h" #include "SWI-Stream.h" int main(int argc, char** argv) { argc = 4; argv[0] = "libpl.dll"; argv[1] = "-G32m"; argv[2] = "-L32m"; argv[3] = "-T32m"; PL_initialise(argc, argv); if ( !PL_initialise(argc, argv) ) PL_halt(1); PlCall( "consult(swi('plwin.rc'))" ); PlCall( "consult('hello.pl')" ); PL_halt( PL_toplevel() ? 0 : 1 ); } So this is how to load a Prolog source code (hello.pl) at run time into VS2008 without having to use plld at the VS command prompt.

    Read the article

  • C89, Mixing Variable Declarations and Code

    - by rutski
    I'm very curious to know why exactly C89 compilers will dump on you when you try to mix variable declarations and code, like this for example: rutski@imac:~$ cat test.c #include <stdio.h> int main(void) { printf("Hello World!\n"); int x = 7; printf("%d!\n", x); return 0; } rutski@imac:~$ gcc -std=c89 -pedantic test.c test.c: In function ‘main’: test.c:7: warning: ISO C90 forbids mixed declarations and code rutski@imac:~$ Yes, you can avoid this sort of thing by staying away from -pedantic. But then your code is no longer standards compliant. And as anybody capable of answering this post probably already knows, this is not just a theoretical concern. Platforms like Microsoft's C compiler enforce this quick in the standard under any and all circumstances. Given how ancient C is, I would imagine that this feature is due to some historical issue dating back to the extraordinary hardware limitations of the 70's, but I don't know the details. Or am I totally wrong there?

    Read the article

  • Newb Question: scanf() in C

    - by riemannliness
    So I started learning C today, and as an exercise i was told to write a program that asks the user for numbers until they type a 0, then adds the even ones and the odd ones together. Here is is (don't laugh at my bad style): #include <stdio.h>; int main() { int esum = 0, osum = 0; int n, mod; puts("Please enter some numbers, 0 to terminate:"); scanf("%d", &n); while (n != 0) { mod = n % 2; switch(mod) { case 0: esum += n; break; case 1: osum += n; } scanf("%d", &n); } printf("The sum of evens:%d,\t The sum of odds:%d", esum, osum); return 0; } My question concerns the mechanics of the scanf() function. It seems that when you enter several numbers at once separated by spaces (eg. 1 22 34 2 8), the scanf() function somehow remembers each distinct numbers in the line, and steps through the while loop for each one respectively. Why/how does this happen? Example interaction within command prompt: - Please enter some numbers, 0 to terminate: 42 8 77 23 11 (enter) 0 (enter) - The sum of evens:50, The sum of odds:111 I'm running the program through the command prompt, it's compiled for win32 platforms with visual studio.

    Read the article

  • fgets in c don't return a portion of an string

    - by Marc
    Hi! I'm totally new in C, and I'm trying to do a little application that searches a string into a file, my problem is that I need to open a big file (more than 1GB) with just one line inside and fgets return me the entire file (I'm doing test with a 10KB file). actually this is my code: #include <stdio.h> #include <string.h> int main(int argc, char *argv[]) { char *search = argv[argc-1]; int retro = strlen(search); int pun = 0; int sortida; int limit = 10; char ara[20]; FILE *fp; if ((fp = fopen ("SEARCHFILE", "r")) == NULL){ sortida = -1; exit (1); } while(!feof(fp)){ if (fgets(ara, 20, fp) == NULL){ break; } //this must be a 20 bytes line, but it gets the entyre 10Kb file printf("%s",ara); } sortida = 1; if(fclose(fp) != 0){ sortida = -2; exit (1); } return 0; } What can I do to find an string into a file? I'v tried with GREP but it don't helps, because it returns the position:ENTIRE_STRING. I'm open to ideas. Thanks in advance!

    Read the article

  • How do calculators work with precision?

    - by zoul
    Hello! I wonder how calculators work with precision. For example the value of sin(M_PI) is not exactly zero when computed in double precision: #include <math.h> #include <stdio.h> int main() { double x = sin(M_PI); printf("%.20f\n", x); // 0.00000000000000012246 return 0; } Now I would certainly want to print zero when user enters sin(p). I can easily round somewhere on 1e–15 to make this particular case work, but that’s a hack, not a solution. When I start to round like this and the user enters something like 1e–20, they get a zero back (because of the rounding). The same thing happens when the user enters 1/10 and hits the = key repeatedly — when he reaches the rounding treshold, he gets zero. And yet some calculators return plain zero for sin(p) and at the same time they can work with expressions such as (1e–20)/10 comfortably. Where’s the trick?

    Read the article

  • Help me with the simplest program for "Trusted" application

    - by idazuwaika
    Hi, I hope anyone from the large community here can help me write the simplest "Trusted" program that I can expand from. I'm using Ubuntu Linux 9.04, with TPM emulator 0.60 from Mario Strasser (http://tpm-emulator.berlios.de/). I have installed the emulator and Trousers, and can successfully run programs from tpm-tools after running tpmd and tcsd daemons. I hope to start developing my application, but I have problems compiling the code below. #include <trousers/tss.h> #include <trousers/trousers.h> #include <stdio.h> TSS_HCONTEXT hContext; int main() { Tspi_Context_Create(&hContext); Tspi_Context_Close(hContext); return 0; } After trying to compile with g++ tpm.cpp -o tpmexe I receive errors undefined reference to 'Tspi_Context_Create' undefined reference to 'Tspi_Context_Close' What do I have to #include to successfully compile this? Is there anything that I miss? I'm familiar with C, but not exactly so with Linux/Unix programming environment. ps: I am a part time student in Master in Information Security programme. My involvement with programming has been largely for academic purposes.

    Read the article

  • C++ Check Substring of a String

    - by user69514
    I'm trying to check whether or not the second argument in my program is a substring of the first argument. The problem is that it only work if the substring starts with the same letter of the string. .i.e Michigan - Mich (this works) Michigan - Mi (this works) Michigan - igan (this doesn't work) #include <stdio.h> #include <string.h> #include <string> using namespace std; bool my_strstr( string str, string sub ) { bool flag = true; int startPosition = -1; char subStart = str.at(0); char strStart; //find starting position for(int i=0; i<str.length(); i++){ if(str.at(i) == subStart){ startPosition = i; break; } } for(int i=0; i<sub.size(); i++){ if(sub.at(i) != str.at(startPosition)){ flag = false; break; } startPosition++; } return flag; } int main(int argc, char **argv){ if (argc != 3) { printf ("Usage: check <string one> <string two>\n"); } string str1 = argv[1]; string str2 = argv[2]; bool result = my_strstr(str1, str2); if(result == 1){ printf("%s is a substring of %s\n", argv[2], argv[1]); } else{ printf("%s is not a substring of %s\n", argv[2], argv[1]); } return 0; }

    Read the article

  • I am trying to find how many vowels and consonants in my string in C

    - by John Walter
    #include <stdio.h> #include <string.h> int main() { int i; int counter=0, counter2=0; char *s; char name[30]; char vowel[6] = "AEIOU"; char consonants[21] = "BCDFGHJKLMNPQRSTVWXYZ"; printf ("input the string: "); scanf ("%s", name); printf ("The string is %s\n", name); for (i=0; name[i]!='\0'; i++) { if (s = strchr(vowel, name[i])) { counter++; } else if (s =strchr(consonants, name[i])) { counter2++; } printf ("First counter is %d\n", counter); printf ("The second counter is %d\n", counter2); return 0; } } And the question is, what is wrong with my code? why counter is not working? Because I tried a lot of ways, and nothing works, maybe someone can explain for me.

    Read the article

  • Doubts in executable and relocatable object file

    - by bala1486
    Hello, I have written a simple Hello World program. #include <stdio.h> int main() { printf("Hello World"); return 0; } I wanted to understand how the relocatable object file and executable file look like. The object file corresponding to the main function is 0000000000000000 <main>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: bf 00 00 00 00 mov $0x0,%edi 9: b8 00 00 00 00 mov $0x0,%eax e: e8 00 00 00 00 callq 13 <main+0x13> 13: b8 00 00 00 00 mov $0x0,%eax 18: c9 leaveq 19: c3 retq Here the function call for printf is callq 13. One thing i don't understand is why is it 13. That means call the function at adresss 13, right??. 13 has the next instruction, right?? Please explain me what does this mean?? The executable code corresponding to main is 00000000004004cc <main>: 4004cc: 55 push %rbp 4004cd: 48 89 e5 mov %rsp,%rbp 4004d0: bf dc 05 40 00 mov $0x4005dc,%edi 4004d5: b8 00 00 00 00 mov $0x0,%eax 4004da: e8 e1 fe ff ff callq 4003c0 <printf@plt> 4004df: b8 00 00 00 00 mov $0x0,%eax 4004e4: c9 leaveq 4004e5: c3 retq Here it is callq 4003c0. But the binary instruction is e8 e1 fe ff ff. There is nothing that corresponds to 4003c0. What is that i am getting wrong? Thanks. Bala

    Read the article

  • program won't find math.h anymore

    - by 130490868091234
    After a long time, I downloaded a program I co-developed and tried to recompile it on my Ubuntu Linux 12.04, but it seems it does not find math.h anymore. This may be because something has changed recently in gcc, but I can't figure out if it's something wrong in src/Makefile.am or a missing dependency: Download from http://www.ub.edu/softevol/variscan/: tar xzf variscan-2.0.2.tar.gz cd variscan-2.0.2/ make distclean sh ./autogen.sh make I get: [...] gcc -DNDEBUG -O3 -W -Wall -ansi -pedantic -lm -o variscan variscan.o statistics.o common.o linefile.o memalloc.o dlist.o errabort.o dystring.o intExp.o kxTok.o pop.o window.o free.o output.o readphylip.o readaxt.o readmga.o readmaf.o readhapmap.o readxmfa.o readmav.o ran1.o swcolumn.o swnet.o swpoly.o swref.o statistics.o: In function `calculate_Fu_and_Li_D': statistics.c:(.text+0x497): undefined reference to `sqrt' statistics.o: In function `calculate_Fu_and_Li_F': statistics.c:(.text+0x569): undefined reference to `sqrt' statistics.o: In function `calculate_Fu_and_Li_D_star': statistics.c:(.text+0x63b): undefined reference to `sqrt' statistics.o: In function `calculate_Fu_and_Li_F_star': statistics.c:(.text+0x75c): undefined reference to `sqrt' statistics.o: In function `calculate_Tajima_D': statistics.c:(.text+0x85d): undefined reference to `sqrt' statistics.o:statistics.c:(.text+0xcb1): more undefined references to `sqrt' follow statistics.o: In function `calcRunMode21Stats': statistics.c:(.text+0xe02): undefined reference to `log' statistics.o: In function `correctedDivergence': statistics.c:(.text+0xe5a): undefined reference to `log' statistics.o: In function `calcRunMode22Stats': statistics.c:(.text+0x104a): undefined reference to `sqrt' statistics.o: In function `calculate_Fu_fs': statistics.c:(.text+0x11a8): undefined reference to `fabsl' statistics.c:(.text+0x11ca): undefined reference to `powl' statistics.c:(.text+0x11f2): undefined reference to `logl' statistics.o: In function `calculateStatistics': statistics.c:(.text+0x13f2): undefined reference to `log' collect2: ld returned 1 exit status make[1]: *** [variscan] Error 1 make[1]: Leaving directory `/home/avilella/variscan/latest/variscan-2.0.2/src' make: *** [all-recursive] Error 1 The libraries are there because this simple example works perfectly well: $ gcc test.c -o test -lm $ cat test.c #include <stdio.h> #include <math.h> int main(void) { double x = 0.5; double result = sqrt(x); printf("The hyperbolic cosine of %lf is %lf\n", x, result); return 0; } Any ideas?

    Read the article

  • select failing with C program but not shell

    - by Gary
    So I have a parent and child process, and the parent can read output from the child and send to the input of the child. So far, everything has been working fine with shell scripts, testing commands which input and output data. I just tested with a simple C program and couldn't get it to work. Here's the C program: #include <stdio.h> int main( void ) { char stuff[80]; printf("Enter some stuff:\n"); scanf("%s", stuff); return 0; } The problem with with the C program is that my select fails to read from the child fd and hence the program cannot finish. Here's the bit that does the select.. //wait till child is ready fd_set set; struct timeval timeout; FD_ZERO( &set ); // initialize fd set FD_SET( PARENT_READ, &set ); // add child in to set timeout.tv_sec = 3; timeout.tv_usec = 0; int r = select(FD_SETSIZE, &set, NULL, NULL, &timeout); if( r < 1 ) { // we didn't get any input exit(1); } Does anyone have any idea why this would happen with the C program and not a shell one? Thanks!

    Read the article

  • Error when linking C executable to OpenCV

    - by Ghilas BELHADJ
    I'm compiling OpenCV under Ubuntu 13.10 using cMake. i've already compiled c++ programs and they works well. now i'm trying to compile a C file using this cMakeLists.txt cmake_minimum_required (VERSION 2.8) project (hello) find_package (OpenCV REQUIRED) add_executable (hello src/test.c) target_link_libraries (hello ${OpenCV_LIBS}) here is the test.c file: #include <stdio.h> #include <stdlib.h> #include <opencv/highgui.h> int main (int argc, char* argv[]) { IplImage* img = NULL; const char* window_title = "Hello, OpenCV!"; if (argc < 2) { fprintf (stderr, "usage: %s IMAGE\n", argv[0]); return EXIT_FAILURE; } img = cvLoadImage(argv[1], CV_LOAD_IMAGE_UNCHANGED); if (img == NULL) { fprintf (stderr, "couldn't open image file: %s\n", argv[1]); return EXIT_FAILURE; } cvNamedWindow (window_title, CV_WINDOW_AUTOSIZE); cvShowImage (window_title, img); cvWaitKey(0); cvDestroyAllWindows(); cvReleaseImage(&img); return EXIT_SUCCESS; } it returns me this error whene running cmake . then make to the project: Linking C executable hello /usr/bin/ld: CMakeFiles/hello.dir/src/test.c.o: undefined reference to symbol «lrint@@GLIBC_2.1» /lib/i386-linux-gnu/libm.so.6: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status make[2]: *** [hello] Erreur 1 make[1]: *** [CMakeFiles/hello.dir/all] Erreur 2 make: *** [all] Erreur 2

    Read the article

  • Horizontal histogram won't accept input after the first input

    - by vincentbelkin
    So I'm making a program which is supposed to print a horizontal histogram of the lengths of words in its input. I don't know if most of it is OK since the main problem is it won't accept any input after the first one. Oh I also put comments on the parts I'm having some trouble with, like how to print "-" multiple times in order to represent histogram. I've tried making other versions of the code but I couldn't check if I'm close to getting it because again it won't accept another input after the first input. /*Write a program to print a histogram of the lengths of words in its input. It is easy to draw the histogram with the bars horizontal*/ #include <stdio.h> #define MAX 30 #define IN 1 #define OUT 0 int main() { int a,c,i,k,state,word[MAX]; a=0; k=0; state=OUT; for(i=0;i<MAX;i++) word[i]=0; while((c=getchar())!=EOF) { if(c==' '||c=='\t'||c=='\n') state=OUT; else state=IN; while(state==IN) a++; if(state==OUT) { word[i]=a; i++; } /*This part is hard for me, I don't know how to print X multiple times!*/ if((c==getchar())&&c==EOF) { for(i=0;i<MAX;i++) { for(i=0;i<=word[i];i++) putchar('-'); putchar('\n'); } } } }

    Read the article

  • Equivalent to window.setTimeout() for C++

    - by bobobobo
    In javascript there's this sweet, sweet function window.setTimeout( func, 1000 ) ; which will asynchronously invoke func after 1000 ms. I want to do something similar in C++ (without multithreading), so I put together a sample loop like: #include <stdio.h> struct Callback { // The _time_ this function will be executed. double execTime ; // The function to execute after execTime has passed void* func ; } ; // Sample function to execute void go() { puts( "GO" ) ; } // Global program-wide sense of time double time ; int main() { // start the timer time = 0 ; // Make a sample callback Callback c1 ; c1.execTime = 10000 ; c1.func = go ; while( 1 ) { // its time to execute it if( time c1.execTime ) { c1.func ; // !! doesn't work! } time++; } } How can I make something like this work?

    Read the article

  • how to fix my error saying expected expression before 'else'

    - by user292489
    this program intended to read a .txt, a set of numbers, file and wwrite to another two .txt files called even amd odd as follows: #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { int i=0,even,odd; int number[i]; // check to make sure that all the file names are entered if (argc != 3) { printf("Usage: executable in_file output_file\n"); exit(0); } FILE *dog = fopen(argv[1], "r"); FILE *feven= fopen(argv[2], "w"); FILE *fodd= fopen (argv[3], "w"); // check whether the file has been opened successfully if (dog == NULL) { printf("File %s cannot open!\n", argv[1]); exit(0); } //odd = fopen(argv[2], "w"); { if (i%2!=1) i++;} fprintf(feven, "%d", even); fscanf(dog, "%d", &number[i]); else { i%2==1; i++;} fprintf(fodd, "%d", odd); fscanf(dog, "%d", &number[i]); fclose(feven); fclose(fodd);

    Read the article

  • dynamic lib can't find static lib

    - by renyufei
    env: gcc version 4.4.1 (Ubuntu 4.4.1-4ubuntu9) app: Bin(main) calls dynamic lib(testb.so), and testb.so contains a static lib(libtesta.a). file list: main.c test.h a.c b.c then compile as: gcc -o testa.o -c a.c ar -r libtesta.a testa.o gcc -shared -fPIC -o testb.so b.c gcc -o main main.c -L. -ltesta -ldl then compile success, but runs an error: ./main: symbol lookup error: ./testb.so: undefined symbol: print code as follows: test.h #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <dlfcn.h> int printa(const char *msg); int printb(const char *msg); a.c #include "test.h" int printa(const char *msg) { printf("\tin printa\n"); printf("\t%s\n", msg); } b.c #include "test.h" int printb(const char *msg) { printf("in printb\n"); printa("called by printb\n"); printf("%s\n", msg); } main.c #include "test.h" int main(int argc, char **argv) { void *handle; int (*dfn)(const char *); printf("before dlopen\n"); handle = dlopen("./testb.so", RTLD_LOCAL | RTLD_LAZY); printf("after dlopen\n"); if (handle == NULL) { printf("dlopen fail: [%d][%s][%s]\n", \ errno, strerror(errno), dlerror()); exit(EXIT_FAILURE); } printf("before dlsym\n"); dfn = dlsym(handle, "printb"); printf("after dlsym\n"); if (dfn == NULL) { printf("dlsym fail: [%d][%s][%s]\n", \ errno, strerror(errno), dlerror()); exit(EXIT_FAILURE); } printf("before dfn\n"); dfn("printb func\n"); printf("after dfn\n"); exit(EXIT_SUCCESS); }

    Read the article

  • Hi I am facing a fragmentation error while executing this code? Can someone explain why?

    - by aks
    #include<stdio.h> struct table { char *ipAddress; char *domainName; struct table *next; }; struct table *head = NULL; void add_rec(); void show_rec(); int main() { add_rec(); show_rec(); return 0; } void add_rec() { struct table * temp = head; struct table * temp1 = (struct table *)malloc(sizeof(struct table)); if(!temp1) printf("\n Unable to allocate memory \n"); printf("Enter the ip address you want \n"); scanf("%s",temp1->ipAddress); printf("\nEnter the domain name you want \n"); scanf("%s",temp1->domainName); if(!temp) { head = temp; } else { while(temp->next!=NULL) temp = temp->next; temp->next = temp1; } } void show_rec() { struct table * temp = head; if(!temp) printf("\n No entry exists \n"); while(temp!=NULL) { printf("ipAddress = %s\t domainName = %s\n",temp->ipAddress,temp->domainName); temp = temp->next; } } When i execute this code and enters the IP address for the first node, i am facing fragmentation error. The code crashed. Can someone enlighten?

    Read the article

  • Xlib.h and Xutil.h not found in Eclipse, how can I fix this?

    - by eclipseNoob
    Hi, I'm a newbie to Eclipse IDE for C/C++ development. I just installed MingW and set it up as my system's environment variable. I am trying to make an application that uses the X library but eclipse cant seem to find it. Eclipse works with any other simple standard library functions but it cant find the X library. Please Help! Here's a sample code snippet that's failing: #include <stdio.h> #include <X11/Xlib.h> // Can't find this #include <X11/Xutil.h> // Or this... int main() { printf("Hello"); return 0; } Do I have to download the X library from somewhere? If so then from where and where do I paste it to? Please tell me what to do in order for me to start coding using the Xlib in Eclipse. If you find any useful links, please dont hesitate to post. Thanks.

    Read the article

  • segmentation fault in file operations in c

    - by mekasperasky
    #include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i; char a,b[20],c; FILE *fp1; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; while(1) { a=fgetc(fp1); if(a !="") { b[i]=a; } else { fprintf(fp1, "%.20s\n", b); i=0; continue; } i=i+1; /*Switch(a) { case EOF :return eof; case '+':sym=sym+1; case '-':sym=sym+1; case '*':sym=sym+1; case '/':sym=sym+1; case '%':sym=sym+1; case ' */ } return 0; } how does this code end up in segmentation fault?

    Read the article

< Previous Page | 16 17 18 19 20 21 22 23 24 25 26 27  | Next Page >