c('PL_query')

Documentation
- Reference manual
  - Foreign Language Interface
    - The Foreign Include File
      - Querying Prolog
        
        PL_query()
- Packages

Availability:C-language interface function

long PL_query(int)

Obtain status information on the Prolog system. The actual argument type depends on the information required. int describes what information is wanted.^{233Returning
pointers and integers as a long is bad style. The signature of this
function should be changed.} The options are given in table 9.

PL_QUERY_ARGC Return an integer holding the number of arguments given to Prolog from Unix.

PL_QUERY_ARGV Return a char ** holding the argument vector given to Prolog from Unix.

PL_QUERY_SYMBOLFILE Return a char * holding the current symbol file of the running process.

PL_MAX_INTEGER Return a long, representing the maximal integer value represented by a Prolog integer.

PL_MIN_INTEGER Return a long, representing the minimal integer value.

PL_QUERY_VERSION Return a long, representing the version as 10,000 × M + 100 × m + p, where M is the major, m the minor version number and p the patch level. For example, 20717 means 2.7.17.

PL_QUERY_ENCODING Return the default stream encoding of Prolog (of type IOENC).

PL_QUERY_USER_CPU Get amount of user CPU time of the process in milliseconds.

Table 9 : PL_query() options

`PL_QUERY_ARGC`	Return an integer holding the number of arguments given to Prolog from Unix.
`PL_QUERY_ARGV`	Return a `char **` holding the argument vector given to Prolog from Unix.
`PL_QUERY_SYMBOLFILE`	Return a `char *` holding the current symbol file of the running process.
`PL_MAX_INTEGER`	Return a long, representing the maximal integer value represented by a Prolog integer.
`PL_MIN_INTEGER`	Return a long, representing the minimal integer value.
`PL_QUERY_VERSION`	Return a long, representing the version as `10,000 × M + 100 × m + p`, where `M` is the major, `m` the minor version number and `p` the patch level. For example, `20717` means `2.7.17`.
`PL_QUERY_ENCODING`	Return the default stream encoding of Prolog (of type `IOENC`).
`PL_QUERY_USER_CPU`	Get amount of user CPU time of the process in milliseconds.