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cfilebytefwrite

Writing bytes into an executable file in c

I'm actually trying to encrypt some files using a c program. So what i did is reading the file, storing the bytes in a variable, spliting the variable into to (to encrypt it using Blowfish), joining the two variables again into one and writing it to a file, but when debugging the program I always get a Segmentation Fault in this part wich is the last one :

newFile = fopen(newPath,"ab+");
fwrite(&srvBuf,1,BUFF_SIZE,newFile);
fclose(newFile);
printf("Finished");

/* Where srvBuf is my encrypted bytes, BUFF_SIZE is the size of the file,
   newPath is the new file path */
Solution

    1. You should check that

      newFile != NULL

    Its possible for fopen to fail for many many reasons ( directory does not exist, user lacks permissions etc. )

    1. You don't show the code for how srvBuf is written, or how big it is. The error can easily be there. Are you sure that srvBuf is BUFF_SIZE bytes long?