Segmentation fault while copying file?

Don't use fprintf it treats its second argument as a format string. Use fwrite .

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I'm a beginner and I'm trying to copy the content of a very large text file of size around 33MB ( 33136KB precisely ) to a new file. I'm getting segmentation fault while running the program. Only 16KB is getting copied to my new file.

The name of file which I'm to copy is "test_file3" and my new file's name is "newfile". I'm doing all this in CentOS-5 in virtual box. Here is the details: root@localhost decomp_trials# cat read_file.

C #include #include int main( int argc, char *argv ) { FILE *ifp, *ofp; char *ptr; ifp = fopen ( argv 1 , "r" ); ofp = fopen ( argv 2 , "a" ); for ( ptr = malloc ( 10 ); fread ( ptr, 1, 10, ifp ); ) fprintf ( ofp, ptr ); fclose ( ifp ); fclose ( ofp ); return 0; } root@localhost decomp_trials# cc read_file. C -o read_file root@localhost decomp_trials# . /read_file /root/sys_cl_huk_ajh/imp/copy_hook7/test_file3 newfile Segmentation fault root@localhost decomp_trials# du -s newfile 16 newfile root@localhost decomp_trials# pwd /root/sys_cl_huk_ajh/pro_jnk/decomp_trials root@localhost decomp_trials# du -s ../../imp/copy_hook7/test_file3 33136 ../../imp/copy_hook7/test_file3 root@localhost decomp_trials# Please tell me what I'm possibly doing wrong.

Is there any better method? Please help me out c fread fprintf file-copy file-copying link|improve this question edited Jan 22 at 13:00skaffman114k8135227 asked Jan 22 at 12:14Ajish Alfred162.

I don't know anything about this, but 16K is awfully like 2^14 – Ali Jan 22 at 12:19.

Don't use fprintf; it treats its second argument as a format string. Use fwrite. As to why it seg-faults, consider what happens if your input data happens to contain e.g. %s.

Fprintf will then start walking through the stack, reading random data until it finds a 0-valued byte (a null terminator). This could easily end up walking into memory that isn't owned by the application.

Thanks.. Now its working! – Ajish Alfred Jan 22 at 17:07.

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