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466
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1 <refentry id="read">
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2 <refnamediv>
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468
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3 <refname>Read</refname>
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574
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4 <refname>Readln</refname>
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468
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5 <refpurpose>read from a file</refpurpose>
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466
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6 </refnamediv>
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7
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8 <refsynopsisdiv>
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9 <funcsynopsis>
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10 <funcprototype>
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11 <funcdef><function>read</function></funcdef>
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574
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12 <paramdef>int <parameter>pn</parameter></paramdef>
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13 <paramdef>char *<parameter>buffer</parameter></paramdef>
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14 <paramdef>int <parameter>count</parameter></paramdef>
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15 </funcprototype>
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16 <funcprototype>
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17 <funcdef><function>readln</function></funcdef>
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18 <paramdef>int <parameter>pn</parameter></paramdef>
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19 <paramdef>char *<parameter>buffer</parameter></paramdef>
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20 <paramdef>int <parameter>count</parameter></paramdef>
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466
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21 </funcprototype>
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22 </funcsynopsis>
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23
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24 </refsynopsisdiv>
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25
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542
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26 <refsect1><title>Assembler Equivalent</title>
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27 <para>
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28 os9 I$READ
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29 </para>
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30 <para>
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31 os9 I$READLN
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32 </para>
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33 </refsect1>
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34
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466
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35 <refsect1><title>Description</title>
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36 <para>
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604
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37 The path number, "pn" is an integer which is one of the
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38 standard path numbers 0, 1, or 2, or the path number should
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39 have been returned by a successful call to "open", "creat", or
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40 "dup". "Buffer" is a pointer to space with at least "count"
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41 bytes of memory into which read will put the data from the
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42 file.
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43 </para>
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44 <para>
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45 It is guaranteed that at most "count" bytes will be read, but
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46 often less will be, either because, for <function>readln</function>, the file
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47 represents a terminal and input stops at the end of a line, or
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48 for both, end-of-file has been reached.
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49 </para>
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50 <para>
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51 Readln causes "line-editing" such as echoin to take place and
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52 returns once the first "\n" is encountered in the input or the
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53 number of bytes requested has been read. Readln is the
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54 preferred call for reading from the user's terminal.
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55 </para>
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56 <para>
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57 Read does not cause any such editing. See the OS-9 manual for
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58 a fuller description of the actions of these calls.
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466
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59 </para>
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60 </refsect1>
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542
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61
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552
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62 <refsect1><title>Diagnostics</title>
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63 <para>
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64 Read and readln return the number of bytes actually read (0 at
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65 end-of-file) or -1 for physical i/o errors, a bad path number,
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66 or a ridicolous "count".
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67 </para>
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68 <para>
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69 NOTE that end-of-file is not considered an error, and no error
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70 indication is returned. Zero is returned on EOF.
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71 </para>
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72 </refsect1>
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73
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542
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74 <refsect1><title>See Also</title>
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75 <para>
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76 <link linkend="open">open()</link>,
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77 <link linkend="creat">creat()</link>,
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78 <link linkend="dup">dup()</link>
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79 </para>
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80 </refsect1>
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81
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466
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82 </refentry>
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