C编译器：“类型'char *'和'int'不是赋值兼容的” - 但是没有int？

Question

I'm porting a FOSS package to HP-UX. I'm down to one compiler warning I just cannot figure out. I should note I'm using HP-UX's bundled free /usr/bin/cc, not the add-on purchased compiler, in order to make the package as widely usable as possible.

The compile (which is just cc with no flags) says:

Warning 942: "grep.c", line 288 # Types 'char *' and 'int' are not assignment-compatible.
        if ((fname = strsep(&lp, ":")) == NULL)
             ^^^^^^^^^^^^^^^^

fname in that function is declared:

    char    *fname, *line, *lp, *ln;

So fname is a char ptr. And that's what strsep() returns:

char *strsep(char **stringp, const char *delim) {

strsep is included from OpenBSD: http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/string/strsep.c?rev=1.6;content-type=text%2Fplain

So...strsep returns a char pointer, and that's what fname is. strsep can only return a character pointer or NULL. So where is the 'int' in all of this?

Answer 1

Did you #include a header file that properly defines strsep() ? If not, then the traditional thing to do is assume that the function returns int , which is what's probably causing your issue.

Answer 2

I'd guess that your headers aren't declaring strsep at all since it is non-standard, that would lead the compiler to assume that it returns int and there's your error. Try adding -D_BSD_SOURCE to your compiler options (or isolate that to only apply to string.h . If that doesn't work, grep through the system headers (or the man pages) to figure out if there is a prototype for strsep anywhere and what sort of macro dance you need to get at it. As a last resort (assuming you have it in your libc) you can prototype it yourself.

Also, I think you can replace strsep with the standard strtok with some modifications to the surrounding code. They serve the same purpose but do it with slightly different interfaces.