This looks like a EGCS bug to me: #include "stdio.h" FILE *prerror = stderr; main() { } Put the above lines in a.c and type gcc -c a.c Gives error - initializer is not a constant This used to work with Redhat 5.2 and it also works with SCO Unix, Solaris, IRIX, AIX etc.
It's not an egcs bug. It's part of glibc 2.1; stdin/stdout/stderr are *NOT* constants, so you can't do initialization like that. Initialize the filehandle when you use it to stderr if you like... From the GLIBC FAQ: I get compiler messages "Initializer element not constant" with stdin/stdout/stderr. Why? Constructs like: static FILE *InPtr = stdin; lead to this message. This is correct behaviour with glibc since stdin is not a constant expression. Please note that a strict reading of ISO C does not allow above constructs. One of the advantages of this is that you can assign to stdin, stdout, and stderr just like any other global variable (e.g. `stdout = my_stream;'), which can be very useful with custom streams that you can write with libio (but beware this is not necessarily portable). The reason to implement it this way were versioning problems with the size of the FILE structure. To fix those programs you've got to initialize the variable at run time. This can be done, e.g. in main, like: static FILE *InPtr; int main(void) { InPtr = stdin; } or by constructors (beware this is gcc specific): static FILE *InPtr; static void inPtr_construct (void) __attribute__((constructor)); static void inPtr_construct (void) { InPtr = stdin; }