parsing contents of string into substrings - c

Question

I am trying to read in a string from a file, then parse the contents of the string to determine how many children to create with fork(), and send each child a section of the string.
int main() {
FILE * fp = fopen("Makefiletest", "r");
char * s;
int i;
char * e;
int c;
for (c = 0; c < 7; c++) {
fgets(s, 128, fp);
}
//e = strchr(s, ":");
//i = (int)(e - s);
//printf("index of : is %d\n", i);
printf("%s", s);
for (i = 0; s[i]; s[i]=='.' ? i++ : *s++);
printf("%d\n", i);
return 0;
}
which retrieves the line "maketools.a: parse.o find.o"
maketools.a is a 2nd generation child (that will have received the string "maketools.a" from its parent), and needs to create 2 new 3rd generation children one with the string "parse.o" the other with "find.o".
I ran into a dead end when I was unable to get the index of : due to segmentation faults (it is commented out and replaced with an attempt I was trying to do with counting instead of strings (it failed)), which prevented me from dividing up the string.
UPDATE
int main() {
FILE * fp = fopen("Makefiletest", "r");
char * s[256];
int i, index, ind;
char * e;
int c;
for (c = 0; c < 7; c++) {
fgets(s, 128, fp);
}
e = strchr(s, ":");
index = (int)(e - s);
printf("index of : is %d\n", index);
printf("%s", s);
return 0;
}
UPDATE 2
int main () {
char fgets_string[256];
char * fgets_string_ptr = fgets_string;
strcpy(fgets_string_ptr, " maketools.a: parse.o find.o ");
char depen[6][128]; //[0][] is root, 1+ are dependencies
char * depen_ptr;
int c;
while (isspace(* fgets_string_ptr)) {//removes leading whitepace
fgets_string_ptr++;
}
for (c = 0; strlen(fgets_string_ptr) > 0; c++) {
if (c == 0)
strtok_r(fgets_string_ptr, ":", &depen_ptr);
else {
strtok_r(fgets_string_ptr, " ", &depen_ptr);
}
while (isspace(* depen_ptr)) {//removes leading whitespace
depen_ptr++;
}
strcpy(depen[c], fgets_string_ptr);
strcpy(fgets_string_ptr, depen_ptr);
//printf("%s\n", depen[c]);
}
printf("%s\n", depen[0]);
printf("%s\n", depen[1]);
printf("%s\n", depen[2]);
return 0;
}

Answer 1

Below is a different approach to achieve what you want... Output of the code is
~/code/str % clang a.c -I../zstring -Wno-unused-value
~/code/str % ./a.out
maketools.a
parse.o
find.o
~/code/str %
Instead of locating the : character first and dealing with spaces, you can split your string into tokens by using (space) as the separator first, and then for the first string, you can remove : character.
The code below uses a string library I maintain, and can be downloaded from https://github.com/fnoyanisi/zString (available with BSD license)
#include <stdio.h>
#include <zstring.h>
int main(){
char s[]="maketools.a: parse.o find.o";
printf("%s\n",zStrrmv(zStrtok(s," "),":"));
printf("%s\n",zStrtok(NULL," "));
printf("%s\n",zStrtok(NULL," "));
return 0;
}