C语言中用宏来作注释
C语言 注释 中用
2023-09-11 14:20:28 时间
看了PostgreSQL的代码后，我觉得有不理解的地方，比如：
例如这样的：
/* Options that may appear after CATALOG (on the same line) */ #define BKI_BOOTSTRAP #define BKI_SHARED_RELATION #define BKI_WITHOUT_OIDS #define BKI_ROWTYPE_OID(oid) #define BKI_SCHEMA_MACRO
CATALOG(pg_tablespace,1213) BKI_SHARED_RELATION { NameData spcname; /* tablespace name */ Oid spcowner; /* owner of tablespace */ text spclocation; /* physical location (VAR LENGTH) */ aclitem spcacl[1]; /* access permissions (VAR LENGTH) */ text spcoptions[1]; /* per-tablespace options */ } FormData_pg_tablespace;
我怀疑它就是个注释的作用。所以我也实验了一把：
[pgsql@localhost tst]$ cat gao01.c #include <stdio.h> #include <stdlib.h> #define MAN #define WOMAN int main(){ typedef struct MAN { int m_id; int m_age; } Human_A; typedef struct WOMAN { int m_id; int m_age; } Human_B; typedef Human_A *Human_A_ptr; typedef Human_B *Human_B_ptr; Human_A_ptr gao01; Human_B_ptr gao02; gao01= (Human_A_ptr) malloc( sizeof(Human_A)); gao01->m_id=1; gao01->m_age=25; free(gao01); gao02 = (Human_B_ptr) malloc(sizeof(Human_B)); gao02->m_id=2; gao02->m_age=20; free(gao02); return 0; } [pgsql@localhost tst]$