FunctionCall

FunctionCall is a frontend protocol message. Identifies the message as a function call.

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Direction: Frontend → backend
First wire field: Byte1('F')
Field entries: 9
Documented flow contexts: Function Call
direction: F
manual path: /docs/18/protocol-message-formats.html
signature: FunctionCall (F)

版本定义 PG 18

Byte1('F'): Identifies the message as a function call.
Int32: Length of message contents in bytes, including self.
Int32: Specifies the object ID of the function to call.
Int16: The number of argument format codes that follow (denoted C below). This can be zero to indicate that there are no arguments or that the arguments all use the default format (text); or one, in which case the specified format code is applied to all arguments; or it can equal the actual number of arguments.
Int16[C]: The argument format codes. Each must presently be zero (text) or one (binary).
Int16: Specifies the number of arguments being supplied to the function.

Next, the following pair of fields appear for each argument:

Int32: The length of the argument value, in bytes (this count does not include itself). Can be zero. As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case.
Byten: The value of the argument, in the format indicated by the associated format code. n is the above length.

After the last argument, the following field appears:

Int16: The format code for the function result. Must presently be zero (text) or one (binary).

Wire fields in documented order

Position	Format	Meaning
1	Byte1('F')	Identifies the message as a function call.
2	Int32	Length of message contents in bytes, including self.
3	Int32	Specifies the object ID of the function to call.
4	Int16	The number of argument format codes that follow (denoted C below). This can be zero to indicate that there are no arguments or that the arguments all use the default format (text); or one, in which case the specified format code is applied to all arguments; or it can equal the actual number of arguments.
5	Int16[ C ]	The argument format codes. Each must presently be zero (text) or one (binary).
6	Int16	Specifies the number of arguments being supplied to the function.
7	Int32	The length of the argument value, in bytes (this count does not include itself). Can be zero. As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case.
8	Byte n	The value of the argument, in the format indicated by the associated format code. n is the above length.
9	Int16	The format code for the function result. Must presently be zero (text) or one (binary).

比较版本

完整来源事实

fields

map[description:Identifies the message as a function call. format:Byte1('F')], map[description:Length of message contents in bytes, including self. format:Int32], map[description:Specifies the object ID of the function to call. format:Int32], map[description:The number of argument format codes that follow (denoted C below). This can be zero to indicate that there are no arguments or that the arguments all use the default format (text); or one, in which case the specified format code is applied to all arguments; or it can equal the actual number of arguments. format:Int16], map[description:The argument format codes. Each must presently be zero (text) or one (binary). format:Int16[ C ]], map[description:Specifies the number of arguments being supplied to the function. format:Int16], map[description:The length of the argument value, in bytes (this count does not include itself). Can be zero. As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case. format:Int32], map[description:The value of the argument, in the format indicated by the associated format code. n is the above length. format:Byte n], map[description:The format code for the function result. Must presently be zero (text) or one (binary). format:Int16]

来源引用

完整定义与证据 JSON

定义来源

center · PostgreSQL 18 · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f

正文语言: en · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f