🚀 go-pugleaf

Sept. 8, 1992

Hello FSF,

    I'm having two problems with GNU C v1.39 running under Sun OS 4.1.1 on a
SPARC system.

    The first involves the function ungetc().  Here is a file that
demonstrates the problem.  (This code comes from the file
lread.c which is part of the distribution for ATT's fortran to C converter
f2c.  lread.c is part of the library libI77.)

#include  "stdio.h"


int (*l_ungetc)();

/*
    inserting this line allows the code to complile
#define ungetc
*/

#ifdef ungetc
 static int
#ifdef KR_headers
un_getc(x,cf) int x; FILE *cf;
#else
un_getc(int x, FILE *cf)
#endif
{ return ungetc(x,cf); }
#else
#define un_getc ungetc
#ifdef KR_headers
 extern int ungetc();
#endif
#endif

int AFunction()
{
    l_ungetc = un_getc;
    return (0);
}


Apparently if ungetc isn't #defined the user is supposed to supply their own.
However, gcc thinks that ungetc is not #defined, so the macro un_getc gets
set to ungetc.  (I'm not using KR_headers.)

   The compiler generates the following error message:

lread.c: In function s_rsle:
lread.c:584: `ungetc' undeclared (first use this function)
lread.c:584: (Each undeclared identifier is reported only once
lread.c:584: for each function it appears in.)

    How is ungetc() implemented in GNU C?  I can't find a prototype for it
in any of the header files, but it exists in one of the libraries and other
code that uses it works.  I've also tried compiling with the -E switch to
see if ungetc() was implemented as a macro, but it isn't.

    I got the code to compile by placing a

#define ungetc

before the

#ifdef ungetc

statement.  If ungetc is a library function why isn't there a prototype for
it?  If it is "built in" to GNU C why isn't the compiler aware of it when
cpp encounters the

#ifdef ungetc

statement?

    The second problem involves the function strtoul().  It doesn't seem to
exist in GNU C v1.39.  Does it exist or was it left out of v1.39?


Dean Schulze
schulze@argus.lpl.arizona.edu