我正在使用 zlib.h 构建,我有 v1.2.5 的本地副本,但在 /usr/include/zlib.h 中有 v1.2.1.2。
如果我省略将 -I/my/path/to/zlib 添加到我的 make 中,我会因使用没有 Z_FIXED 的旧版本而出错:
g++ -g -Werror -Wredundant-decls -D_FILE_OFFSET_BITS=64 -c -o ARCH.linux_26_i86/debug/sysParam.o sysParam.cpp
sysParam.cpp: In member function `std::string CSysParamAccess::getCompressionStrategyName() const':
sysParam.cpp:1816: error: `Z_FIXED' was not declared in this scope
sysParam.cpp: In member function `bool CSysParamAccess::setCompressionStrategy(const std::string&, paramSource)':
sysParam.cpp:1849: error: `Z_FIXED' was not declared in this scope
或者,如果我将包含路径添加到我正在使用的 zlib z1.2.5,我会得到双重定义,似乎 zlib.h 被包含两次并带有两组不同的 -D 值,但我不明白如何这正在发生:
g++ -g -Werror -Wredundant-decls -I../../src/zlib-1.2.5 -D_FILE_OFFSET_BITS=64 -c -o ARCH.linux_26_i86/debug/sysParam.o sysParam.cpp
In file included from sysParam.cpp:24:
../../src/zlib-1.2.5/zlib.h:1582: warning: redundant redeclaration of `void* gzopen64(const char*, const char*)' in same scope
../../src/zlib-1.2.5/zlib.h:1566: warning: previous declaration of `void* gzopen64(const char*, const char*)'
../../src/zlib-1.2.5/zlib.h:1583: warning: redundant redeclaration of `long long int gzseek64(void*, long long int, int)' in same scope
../../src/zlib-1.2.5/zlib.h:1567: warning: previous declaration of `off64_t gzseek64(void*, off64_t, int)'
../../src/zlib-1.2.5/zlib.h:1584: warning: redundant redeclaration of `long long int gztell64(void*)' in same scope
../../src/zlib-1.2.5/zlib.h:1568: warning: previous declaration of `off64_t gztell64(void*)'
../../src/zlib-1.2.5/zlib.h:1585: warning: redundant redeclaration of `long long int gzoffset64(void*)' in same scope
../../src/zlib-1.2.5/zlib.h:1569: warning: previous declaration of `off64_t gzoffset64(void*)'
../../src/zlib-1.2.5/zlib.h:1586: warning: redundant redeclaration of `uLong adler32_combine64(uLong, uLong, long long int)' in same scope
../../src/zlib-1.2.5/zlib.h:1570: warning: previous declaration of `uLong adler32_combine64(uLong, uLong, off64_t)'
../../src/zlib-1.2.5/zlib.h:1587: warning: redundant redeclaration of `uLong crc32_combine64(uLong, uLong, long long int)' in same scope
../../src/zlib-1.2.5/zlib.h:1571: warning: previous declaration of `uLong crc32_combine64(uLong, uLong, off64_t)'
这里是上面提到的 zlib.h 中的一些相关行:
// This would be line 1558 of zlib.h
/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
* change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
* both are true, the application gets the *64 functions, and the regular
* functions are changed to 64 bits) -- in case these are set on systems
* without large file support, _LFS64_LARGEFILE must also be true
*/
#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
#endif
#if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
# define gzopen gzopen64
# define gzseek gzseek64
# define gztell gztell64
# define gzoffset gzoffset64
# define adler32_combine adler32_combine64
# define crc32_combine crc32_combine64
# ifdef _LARGEFILE64_SOURCE
ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
# endif
#else
ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
#endif
// This would be line 1597 of zlib.h
我不确定如何进一步追踪这一点。我尝试将 zlib.h 的包含移动到 cpp 文件的包含列表的顶部和底部,但没有任何区别。
将 -E 传递给 g++ 的摘录部分显示:
extern int inflateInit2_ (z_streamp strm, int windowBits, const char *version, int stream_size);
extern int inflateBackInit_ (z_streamp strm, int windowBits, unsigned char *window, const char *version, int stream_size);
# 1566 "../../src/zlib-1.2.5/zlib.h"
extern gzFile gzopen64 (const char *, const char *);
extern off64_t gzseek64 (gzFile, off64_t, int);
extern off64_t gztell64 (gzFile);
extern off64_t gzoffset64 (gzFile);
extern uLong adler32_combine64 (uLong, uLong, off64_t);
extern uLong crc32_combine64 (uLong, uLong, off64_t);
# 1582 "../../src/zlib-1.2.5/zlib.h"
extern gzFile gzopen64 (const char *, const char *);
extern long long gzseek64 (gzFile, long long, int);
extern long long gztell64 (gzFile);
extern long long gzoffset64 (gzFile);
extern uLong adler32_combine64 (uLong, uLong, long long);
extern uLong crc32_combine64 (uLong, uLong, long long);
# 1600 "../../src/zlib-1.2.5/zlib.h"
struct internal_state {int dummy;};
不知道为什么第 1566 行和第 1582 行会在 CPP 输出中一起出现,但因此会发出有关重复声明的警告。