1<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:base="" xml:id="eglQueryString"> 2 <info> 3 <copyright> 4 <year>2003-2018</year> 5 <holder>The Khronos Group Inc.</holder> 6 </copyright> 7 </info> 8 <refmeta> 9 <refentrytitle>eglQueryString</refentrytitle> 10 <manvolnum>3G</manvolnum> 11 </refmeta> 12 <refnamediv> 13 <refname>eglQueryString</refname> 14 <refpurpose> 15 return a string describing properties of the EGL client or of an 16 <acronym>EGL</acronym> display connection 17 </refpurpose> 18 </refnamediv> 19 <refsynopsisdiv> 20 <title>C Specification</title> 21 <funcsynopsis> 22 <funcprototype> 23 <funcdef>char const * <function>eglQueryString</function></funcdef> 24 <paramdef>EGLDisplay <parameter>display</parameter></paramdef> 25 <paramdef>EGLint <parameter>name</parameter></paramdef> 26 </funcprototype> 27 </funcsynopsis> 28 </refsynopsisdiv> 29 <refsect1 xml:id="parameters"><title>Parameters</title> 30 <variablelist> 31 <varlistentry> 32 <term><parameter>display</parameter></term> 33 <listitem> 34 <para> 35 Specifies the EGL display connection. 36 </para> 37 </listitem> 38 </varlistentry> 39 <varlistentry> 40 <term><parameter>name</parameter></term> 41 <listitem> 42 <para> 43 Specifies a symbolic constant, one of 44 <constant>EGL_CLIENT_APIS</constant>, 45 <constant>EGL_VENDOR</constant>, 46 <constant>EGL_VERSION</constant>, or 47 <constant>EGL_EXTENSIONS</constant>. 48 </para> 49 </listitem> 50 </varlistentry> 51 </variablelist> 52 </refsect1> 53 <refsect1 xml:id="description"><title>Description</title> 54 <para> 55 <function>eglQueryString</function> returns a pointer to a 56 static, zero-terminated string describing properties of the EGL 57 client or of an EGL display connection. 58 <parameter>name</parameter> may be one of the following: 59 </para> 60 <variablelist> 61 <varlistentry> 62 <term><constant>EGL_CLIENT_APIS</constant></term> 63 <listitem><para> 64 Returns a string describing which client rendering 65 APIs are supported. The string contains a 66 space-separated list of API names. The list must 67 include at least one of <code>OpenGL</code>, 68 <code>OpenGL_ES</code>, or <code>OpenVG</code>. 69 These strings correspond respectively to values 70 <constant>EGL_OPENGL_API</constant>, 71 <constant>EGL_OPENGL_ES_API</constant>, and 72 <constant>EGL_OPENVG_API</constant> of the 73 <citerefentry><refentrytitle>eglBindAPI</refentrytitle></citerefentry>, 74 <parameter>api</parameter> argument. 75 </para></listitem> 76 </varlistentry> 77 <varlistentry> 78 <term><constant>EGL_VENDOR</constant></term> 79 <listitem><para> 80 Returns the name of the vendor responsible for this EGL 81 implementation. The format and contents of the string 82 are implementation-dependent. 83 </para></listitem> 84 </varlistentry> 85 <varlistentry> 86 <term><constant>EGL_VERSION</constant></term> 87 <listitem> 88 <para> 89 Returns a version or release number. The 90 <constant>EGL_VERSION</constant> string is laid out 91 as follows: 92 </para> 93 <para> 94 <replaceable>major_version</replaceable>.<replaceable>minor_version</replaceable> 95 space 96 <replaceable>vendor_specific_info</replaceable> 97 </para> 98 <para> 99 Both the major and minor portions of the version 100 number are numeric. Their values must match the 101 <parameter>major</parameter> and 102 <parameter>minor</parameter> values returned by 103 <citerefentry><refentrytitle>eglInitialize</refentrytitle></citerefentry>. 104 </para> 105 <para> 106 The vendor-specific information is optional; if 107 present, its format and contents are 108 implementation-specific. 109 </para> 110 </listitem> 111 </varlistentry> 112 <varlistentry> 113 <term><constant>EGL_EXTENSIONS</constant></term> 114 <listitem> 115 <para> 116 Returns a space separated list of supported 117 extensions to EGL. If there are no extensions, then 118 the empty string is returned. 119 </para> 120 <para> 121 If <parameter>display</parameter> is 122 <constant>EGL_NO_DISPLAY</constant>, then the 123 <constant>EGL_EXTENSIONS</constant> string describes 124 the set of supported <firstterm>client 125 extensions</firstterm>. If 126 <parameter>display</parameter> is a valid, 127 initialized display, then the 128 <constant>EGL_EXTENSIONS</constant> string describes 129 the set of <firstterm>display extensions</firstterm> 130 supported by that display. The set of supported 131 client extensions is disjoint from the set of 132 extensions supported by any given display. 133 </para> 134 </listitem> 135 </varlistentry> 136 </variablelist> 137 </refsect1> 138 <refsect1 xml:id="notes"><title>Notes</title> 139 <para> 140 <constant>EGL_CLIENT_APIS</constant> is supported only if 141 the EGL version is 1.2 or greater. 142 </para> 143 <para> 144 A <parameter>display</parameter> of 145 <constant>EGL_NO_DISPLAY</constant> is supported only if the EGL 146 version is 1.5 or greater. 147 </para> 148 </refsect1> 149 <refsect1 xml:id="errors"><title>Errors</title> 150 <para> 151 <constant>NULL</constant> is returned on failure. 152 </para> 153 <para> 154 <constant>EGL_BAD_DISPLAY</constant> is generated if 155 <parameter>display</parameter> is not an EGL display connection, 156 unless <parameter>display</parameter> is 157 <constant>EGL_NO_DISPLAY</constant> and 158 <parameter>name</parameter> is 159 <constant>EGL_EXTENSIONS</constant>. 160 </para> 161 <para> 162 <constant>EGL_NOT_INITIALIZED</constant> is generated if 163 <parameter>display</parameter> is a valid but uninitialized 164 EGLDisplay. 165 </para> 166 <para> 167 <constant>EGL_BAD_PARAMETER</constant> is generated if 168 <parameter>name</parameter> is not an accepted value. 169 </para> 170 </refsect1> 171 <refsect1 xml:id="seealso"><title>See Also</title> 172 <para> 173 <citerefentry><refentrytitle>eglBindAPI</refentrytitle></citerefentry>, 174 <citerefentry><refentrytitle>eglGetDisplay</refentrytitle></citerefentry>, 175 <citerefentry><refentrytitle>eglInitialize</refentrytitle></citerefentry> 176 </para> 177 </refsect1> 178 <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="copyright.xml"/> 179</refentry> 180