gcc4.3 atol string not declared in this scope

时间：2009-04-02 来源：lwhts

GCC 4.3 related build problems: missing #include

In GCC 4.3 the C++ header dependencies have been cleaned up. In the past, compilation would often be quite slow because including a simple header would indirectly include a lot of other headers, even if they were not needed to compile the current code. Many headers have now been cleaned up with the result that compilation is quicker. The downside is that programmers cannot rely on indirect inclusion of headers they may need anymore. Instead, everything that is needed has to be directly referenced with an #include.

Typical errors look like these:

error: 'find' is not a member of 'std'
error: 'exit' was not declared in this scope

Below is a table showing which header needs to be included for a number of common functions:

Functions and defines	Header
find, for_each, sort	algorithm
isalnum, toupper	cctype
INT_MIN, RAND_MAX	climits
printf	cstdio
atoi, free, rand	cstdlib
EXIT_FAILURE	cstdlib
strcmp, memcpy	cstring
auto_ptr	memory
fd_set, mode_t	sys/types.h
typeid	typeinfo

Thu, 10 May 2007; 15:56 — gcc — permanent link

GCC 4.3: common build failures

Even though GCC 4.2 has seen many delays and still hasn't been released (although it's finally getting close), a lot of development has already been done on trunk for the release of GCC 4.3. I started testing 4.3 in March and in addition to finding and reporting compiler issues I have filed bugs on packages that fail to build with GCC 4.3. The idea is to give people an advance warning and to be ready for GCC 4.3 when it will be released.

We have almost 500 bugs related to GCC 4.3 already, mostly due to a clean-up of C++ headers in GCC that has exposed sloppy programming in many programs. Fortunately, these bugs are easy to fix. As I'm finding common mistakes in packages, I will document these problems and way to make sure a program is ready for GCC 4.3.