main.c:(.text+0x29): undefined reference to `mysql_init'

这个错误是因为在编译链接时缺少 MySQL 的库文件，你需要在编译命令中添加 `-lmysqlclient` 参数来链接 MySQL 的库文件。如果你使用的是 CMake，则需要在 CMakeLists.txt 文件中添加 `target_link_libraries(your_project_name mysqlclient)` 来链接 MySQL 的库文件。

相关问题

cc -o ../../bin/lsqfit main.o lsqfit_ls.o block_init.o line.o -L../../lib -ldblock -ldutil /home/ubuntu/software/tcl/tcl8.5.11/lib/libtcl8.5.so -lm -lc /usr/bin/ld: main.o: in function `main': main.c:(.text+0x239): undefined reference to `blk_open_file' /usr/bin/ld: main.c:(.text+0x499): undefined reference to `blk_open_file' /usr/bin/ld: main.c:(.text+0x5e3): undefined reference to `blk_open_file' /usr/bin/ld: main.c:(.text+0x8f9): undefined reference to `blk_open_file' /usr/bin/ld: ../../lib/libdblock.a(skip.o): in function `blk__skip': skip.c:(.text+0xed): undefined reference to `blk__getlines' /usr/bin/ld: skip.c:(.text+0x126): undefined reference to `blk__getlines' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_init_read': read.c:(.text+0x15): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_read_blk': read.c:(.text+0x6a): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_read_data': read.c:(.text+0xad): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk__read_data': read.c:(.text+0x119): undefined reference to `blk__getlines' /usr/bin/ld: read.c:(.text+0x1b2): undefined reference to `blk__getlines' /usr/bin/ld: read.c:(.text+0x1e5): undefined reference to `blk__getlines' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_read_check': read.c:(.text+0x398): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_read_blk_check': read.c:(.text+0x3d6): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk__read_check': read.c:(.text+0x49b): undefined reference to `blk__getlines' /usr/bin/ld: read.c:(.text+0x788): undefined reference to `blk__getlines' /usr/bin/ld: ../../lib/libdblock.a(read.o): in function `blk_print_env': read.c:(.text+0xbdf): undefined reference to `blk__getenv' /usr/bin/ld: ../../lib/libdblock.a(variables.o

这是一个编译链接错误，提示找不到一些函数的定义。可能是由于缺少库文件或路径不正确导致的。

建议检查以下几个方面：

1. 确认是否正确包含所需的头文件和库文件。

2. 检查库文件是否存在于正确的路径中，并且在链接时是否指定了正确的库路径。

3. 检查是否使用了正确的编译器和编译选项。

如果以上方法都无法解决问题，可以尝试重新编译所缺少的库文件，或者使用其他类似的库文件替代。

gcc -Wp,-MD,.cJSON.o.d -I ../include/ -c cJSON.c -o cJSON.o gcc -Wp,-MD,.main.o.d -I ../include/ -c main.c -o main.o gcc -o test cJSON.o main.o -lm -lpthread -l paho-mqtt3c -L ../lib main.o: In function `msgarrvd': main.c:(.text+0x16f): undefined reference to `msg_queue_send' main.c:(.text+0x1c5): undefined reference to `msg_queue_send' main.o: In function `tcpudp': main.c:(.text+0x72f): undefined reference to `msg_queue_send' main.o: In function `main': main.c:(.text+0x1f70): undefined reference to `shm_init' main.c:(.text+0x1f99): undefined reference to `shm_getaddr' collect2: error: ld returned 1 exit status Makefile:21: recipe for target 'test' failed make: *** [test] Error 1

根据你提供的信息，这是一个编译错误，其中包含对未定义的函数的引用。可能的原因是未正确链接所需的库或未正确包含头文件。你需要检查Makefile文件，确保正确链接和包含所需的库和头文件。例如，在此错误中，未定义的函数可能是msg_queue_send、shm_init和shm_getaddr。你需要确保正确链接和包含与这些函数相关的库和头文件。