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d08741eab5
are now separate files "postgres.h" and "postgres_fe.h", which are meant to be the primary include files for backend .c files and frontend .c files respectively. By default, only include files meant for frontend use are installed into the installation include directory. There is a new make target 'make install-all-headers' that adds the whole content of the src/include tree to the installed fileset, for use by people who want to develop server-side code without keeping the complete source tree on hand. Cleaned up a whole lot of crufty and inconsistent header inclusions.
127 lines
3.3 KiB
C
127 lines
3.3 KiB
C
/******************************************************************************
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These are user-defined functions that can be bound to a Postgres backend
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and called by Postgres to execute SQL functions of the same name.
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The calling format for these functions is defined by the CREATE FUNCTION
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SQL statement that binds them to the backend.
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NOTE: this file shows examples of "new style" function call conventions.
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See funcs.c for examples of "old style".
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*****************************************************************************/
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#include "postgres.h" /* general Postgres declarations */
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#include "fmgr.h" /* for argument/result macros */
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#include "executor/executor.h" /* for GetAttributeByName() */
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#include "utils/geo_decls.h" /* for point type */
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/* These prototypes just prevent possible warnings from gcc. */
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Datum add_one(PG_FUNCTION_ARGS);
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Datum add_one_float8(PG_FUNCTION_ARGS);
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Datum makepoint(PG_FUNCTION_ARGS);
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Datum copytext(PG_FUNCTION_ARGS);
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Datum concat_text(PG_FUNCTION_ARGS);
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Datum c_overpaid(PG_FUNCTION_ARGS);
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/* By Value */
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PG_FUNCTION_INFO_V1(add_one);
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Datum
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add_one(PG_FUNCTION_ARGS)
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{
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int32 arg = PG_GETARG_INT32(0);
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PG_RETURN_INT32(arg + 1);
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}
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/* By Reference, Fixed Length */
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PG_FUNCTION_INFO_V1(add_one_float8);
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Datum
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add_one_float8(PG_FUNCTION_ARGS)
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{
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/* The macros for FLOAT8 hide its pass-by-reference nature */
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float8 arg = PG_GETARG_FLOAT8(0);
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PG_RETURN_FLOAT8(arg + 1.0);
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}
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PG_FUNCTION_INFO_V1(makepoint);
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Datum
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makepoint(PG_FUNCTION_ARGS)
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{
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Point *pointx = PG_GETARG_POINT_P(0);
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Point *pointy = PG_GETARG_POINT_P(1);
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Point *new_point = (Point *) palloc(sizeof(Point));
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new_point->x = pointx->x;
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new_point->y = pointy->y;
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PG_RETURN_POINT_P(new_point);
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}
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/* By Reference, Variable Length */
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PG_FUNCTION_INFO_V1(copytext);
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Datum
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copytext(PG_FUNCTION_ARGS)
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{
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text *t = PG_GETARG_TEXT_P(0);
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/*
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* VARSIZE is the total size of the struct in bytes.
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*/
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text *new_t = (text *) palloc(VARSIZE(t));
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VARATT_SIZEP(new_t) = VARSIZE(t);
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/*
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* VARDATA is a pointer to the data region of the struct.
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*/
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memcpy((void *) VARDATA(new_t), /* destination */
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(void *) VARDATA(t), /* source */
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VARSIZE(t)-VARHDRSZ); /* how many bytes */
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PG_RETURN_TEXT_P(new_t);
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}
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PG_FUNCTION_INFO_V1(concat_text);
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Datum
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concat_text(PG_FUNCTION_ARGS)
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{
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text *arg1 = PG_GETARG_TEXT_P(0);
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text *arg2 = PG_GETARG_TEXT_P(1);
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int32 new_text_size = VARSIZE(arg1) + VARSIZE(arg2) - VARHDRSZ;
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text *new_text = (text *) palloc(new_text_size);
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memset((void *) new_text, 0, new_text_size);
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VARATT_SIZEP(new_text) = new_text_size;
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strncpy(VARDATA(new_text), VARDATA(arg1), VARSIZE(arg1)-VARHDRSZ);
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strncat(VARDATA(new_text), VARDATA(arg2), VARSIZE(arg2)-VARHDRSZ);
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PG_RETURN_TEXT_P(new_text);
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}
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/* Composite types */
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PG_FUNCTION_INFO_V1(c_overpaid);
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Datum
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c_overpaid(PG_FUNCTION_ARGS)
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{
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TupleTableSlot *t = (TupleTableSlot *) PG_GETARG_POINTER(0);
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int32 limit = PG_GETARG_INT32(1);
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bool isnull;
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int32 salary;
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salary = DatumGetInt32(GetAttributeByName(t, "salary", &isnull));
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if (isnull)
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PG_RETURN_BOOL(false);
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/* Alternatively, we might prefer to do PG_RETURN_NULL() for null salary */
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PG_RETURN_BOOL(salary > limit);
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}
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