# External Subroutine List > [HTML Version](external-subroutine-list.htm) As described elsewhere, A-Shell includes two types of subroutines: • Those that are "internal" to A-Shell—i.e., are part of the main A-Shell program. They do not exist as discrete programs, are written in C, are linked in to the main A-Shell executable program, and are cannot be modified by users. • The "external" routines are not part of "core A-Shell," exist as separate files and programs, were written in ASB, and can modified if needed. A set of these external routines is provided with A-Shell, and you can see the run files with the extension SBX in DSK0:\[7,6\]. Source code for the routines may be found in the A-Shell SOSLIB. The following table alphabetically lists A-Shell’s external subroutines, most of which have links to more detailed information. | **Routine** | **Function** | |------|------| | [APRNTSCRN](aprntscrn_sbx.htm.md) | Screen Capture. | | APXTEDIT | Documentation pending. | | [ASEXIT](asexitsbr.htm.md) | A hook routine that will be called automatically just before A-Shell exits. | | [ATEAPX](ateapx_sbx.htm.md) | Transfers a file from application server to ATE client PC. | | ATECFX | ATE configuration dialog. See [ATE Reference](https://www.microsabio.net/dist/doc/ate/00ate.html). | | [ATEGFK](ategfk_sbx.htm.md) | Retrieves a file from the PC via the ATE terminal connection. | | ATEPRT | Documentation pending. | | [ATEREG](atereg_sbr.htm.md) | Query and/or update ATE configuration. | | ATHTTP | A variant of [HTTP](http_sbr.htm.md), which see for details. | | ATPXFR | Documentation pending. | | ATSYNC | Documentation pending. | | AUXEXC | Documentation pending. | | [CSV2XL](csv2xl.htm.md) | Converts CSV files to XLS format. | | [EMAILP](emailp_sbx.htm.md) | Email a report. | | EVTMSG | Documentation pending. | | [FNDUSR](fndusr_sbx.htm.md) | Retrieves information about the current (or another) user from the database. | | [INIX](inix_sbx.htm.md) | Read and write to ini files. Thanks Steve Evans\! | | [ISMBLD](ismbld_sbx.htm.md) | Create ISAM 1.0 file. | | [ISMPAR](ismpar_sbx.htm.md) | Return information from the ISAM "rock" about filespec. | | PDFLPR | Documentation pending. | | PRTMAPI | Documentation pending. | | [PRTXLS](export_to_xls.htm.md) | Exports reports from APEX (A-Shell's enhanced screen display) to XLS file. | | PXLCFG | Documentation pending. | | [SBXINP](sbxinp_sbr.htm.md) | INFLD wrapper that simplifies some INFLD operations. Thanks Jorge Tavares\! | | [SCRSTS](scrsts_sbr.htm.md) | Scrolling status window handler. | | [XSHLEX](xshlex_sbr.htm.md) | Platform-independent "Shell Execute." |