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| author | rsc <devnull@localhost> | 2005-01-14 03:45:44 +0000 |
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| committer | rsc <devnull@localhost> | 2005-01-14 03:45:44 +0000 |
| commit | 78e51a8c6678b6e3dff3d619aa786669f531f4bc (patch) | |
| tree | 015e00fde4fc837fd31b705e18d17dc913829388 /man/man3/exec.html | |
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diff --git a/man/man3/exec.html b/man/man3/exec.html new file mode 100644 index 00000000..e5397352 --- /dev/null +++ b/man/man3/exec.html @@ -0,0 +1,146 @@ +<head> +<title>exec(3) - Plan 9 from User Space</title> +<meta content="text/html; charset=utf-8" http-equiv=Content-Type> +</head> +<body bgcolor=#ffffff> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=10><td> +<tr><td width=20><td> +<tr><td width=20><td><b>EXEC(3)</b><td align=right><b>EXEC(3)</b> +<tr><td width=20><td colspan=2> + <br> +<p><font size=+1><b>NAME </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + exec, execl – execute a file<br> + +</table> +<p><font size=+1><b>SYNOPSIS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>#include <u.h><br> + #include <libc.h> + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + <tt><font size=+1>int exec(char *name, char* argv[])<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + <tt><font size=+1>int execl(char *name, ...)<br> + </font></tt> +</table> +<p><font size=+1><b>DESCRIPTION </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <i>Exec</i> and <i>execl</i> overlay the calling process with the named file, + then transfer to the entry point of the image of the file. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + <i>Name</i> points to the name of the file to be executed; it must not + be a directory, and the permissions must allow the current user + to execute it (see <a href="../man3/stat.html"><i>stat</i>(3)</a>). It should also be a valid binary + image, as defined by the local operating system, or a shell script + (see <a href="../man1/rc.html"><i>rc</i>(1)</a>). The first line of a shell script must begin with + <tt><font size=+1>#!</font></tt> followed + by the name of the program to interpret the file and any initial + arguments to that program, for example<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>#!/bin/rc<br> + ls | mc<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + + </table> + When a C program is executed, it is called as follows:<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>void main(int argc, char *argv[])<br> + + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + </font></tt> + + </table> + <i>Argv</i> is a copy of the array of argument pointers passed to <i>exec</i>; + that array must end in a null pointer, and <i>argc</i> is the number + of elements before the null pointer. By convention, the first + argument should be the name of the program to be executed. <i>Execl</i> + is like <i>exec</i> except that <i>argv</i> will be an array of the parameters + that follow <i>name</i> in the call. The last argument to <i>execl</i> must + be a null pointer. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + For a file beginning <tt><font size=+1>#!</font></tt>, the arguments passed to the program (<tt><font size=+1>/bin/rc</font></tt> + in the example above) will be the name of the file being executed, + any arguments on the <tt><font size=+1>#!</font></tt> line, the name of the file again, and + finally the second and subsequent arguments given to the original + <i>exec</i> call. The result honors the two conventions + of a program accepting as argument a file to be interpreted and + <tt><font size=+1>argv[0]</font></tt> naming the file being executed. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + Most attributes of the calling process are carried into the result; + in particular, files remain open across <i>exec</i> (except those opened + with <tt><font size=+1>OCEXEC</font></tt> OR’d into the open mode; see <a href="../man3/open.html"><i>open</i>(3)</a>); and the working + directory and environment (see <a href="../man3/getenv.html"><i>getenv</i>(3)</a>) remain the same. However, + a newly <i>exec’ed</i> process has no notification + handlers (see <a href="../man3/notify.html"><i>notify</i>(3)</a>).<br> + +</table> +<p><font size=+1><b>SOURCE </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <tt><font size=+1>/usr/local/plan9/src/lib9/exec.c<br> + /usr/local/plan9/src/lib9/execl.c<br> + </font></tt> +</table> +<p><font size=+1><b>SEE ALSO </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + <a href="../man1/prof.html"><i>prof</i>(1)</a>, <a href="../man3/intro.html"><i>intro</i>(3)</a>, <a href="../man3/stat.html"><i>stat</i>(3)</a><br> + +</table> +<p><font size=+1><b>DIAGNOSTICS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + If these functions fail, they return and set <i>errstr</i>. There can + be no return from a successful <i>exec</i> or <i>execl</i>; the calling image + is lost.<br> + +</table> +<p><font size=+1><b>BUGS </b></font><br> + +<table border=0 cellpadding=0 cellspacing=0><tr height=2><td><tr><td width=20><td> + + On Unix, unlike on Plan 9, <i>exec</i> and <i>execl</i> use the user’s current + path to locate <i>prog</i>. This is a clumsy way to deal with Unix’s + lack of a union directory for <tt><font size=+1>/bin</font></tt>. + <table border=0 cellpadding=0 cellspacing=0><tr height=5><td></table> + + To avoid name conflicts with the underlying system, <i>exec</i> and <i>execl</i> + are preprocessor macros defined as <i>p9exec</i> and <i>p9execl</i>; see <a href="../man3/intro.html"><i>intro</i>(3)</a>.<br> + +</table> + +<td width=20> +<tr height=20><td> +</table> +<!-- TRAILER --> +<table border=0 cellpadding=0 cellspacing=0 width=100%> +<tr height=15><td width=10><td><td width=10> +<tr><td><td> +<center> +<a href="../../"><img src="../../dist/spaceglenda100.png" alt="Space Glenda" border=1></a> +</center> +</table> +<!-- TRAILER --> +</body></html> |