Development Process

To compile and connect to a libpq source program, perform the following operations:

1. Decompress the release package (for example, openGauss-*.*.0-***-64bit-Libpq.tar.gz). The required header file is stored in the include folder, and the lib folder contains the required libpq library file.

   NOTE: In addition to libpq-fe.h, the include folder contains the header files postgres_ext.h, gs_thread.h, and gs_threadlocal.h by default. These three header files are the dependency files of libpq-fe.h.

2. Include the libpq-fe.h header file.

   #include <libpq-fe.h>
   

3. Provide the -I directory option to provide the installation location of the header files. (Sometimes the compiler looks for the default directory, so this option can be ignored.) Example:

   gcc -I (Directory where the header files are located) -L (Directory where the libpq library is located) testprog.c -lpq
   

4. If the makefile is used, add the following options to variables CPPFLAGS, LDFLAGS, and LIBS:

   CPPFLAGS += -I (Directory where the header files are located)
   LDFLAGS += -L (Directory where the libpq library is located)
   LIBS += -lpq